The present invention relates to a device and method for brazing a heat pipe assembly with copper-silver alloy filler rings to improve heat dissipation efficiency of a heat pipe. The device comprises a brazing furnace and a conveyor. The brazing furnace comprises an open ended passage with a multi-stage brazing heater and cooler. The conveyor comprises an input bracket assembly, an output bracket assembly and a steel mesh belt. The method comprises steps of (A) providing multiple heat pipe components, (B) assembling the heat pipe components to form heat pipe assemblies, (C) injecting mixed gas, (D) turning on the multi-stage brazing heater and cooler, (E) placing the heat pipe assemblies on the conveyor, (F) brazing the heat pipe assemblies to form heat pipes, (G) cooling the heat pipes and (H) removing the heat pipes from the conveyor.